In one form or another, non-healing or chronic and poorly healing wounds constitute a major burden on the UK health system. Moreover, in certain member countries of the EU health expenses relating to wound healing are already approaching the third most expensive drain on health care funding.
Chronic foot ulcers are a major complication of diabetes, accounting for up to 25% of all hospital admissions involving diabetes, and at a cost to the UK National Health Service of £250M annually. Chronic foot ulcers cause substantial morbidity, impair the quality of life, and are the major cause of lower limb amputation. Despite careful attention to foot care, as many as 25% of diabetics develop foot ulcers in their lifetimes. The causes of lower limb ulceration are the same in diabetics as in non-diabetics, namely neuropathy, ischaemia and trauma. However, this “pathogenic triad” predisposes wounds to infection, which can also contribute to the non-healing nature of the wounds.
Current treatment involves removing pressure from the area, debridement, wound dressing and management of infection: surgical resection and vascular reconstruction may be required in more advanced disease, which ultimately may necessitate amputation.
In addition to lower limb ulcers in diabetics, another major resource health cost is created by pressure wounds or ulcers that result, for example, from failure to provide routine nursing or medical care. In the UK 412,000 people are affected annually by this sort of wound at a cost of £1.4-2.1 billion.
The healing of a wound is controlled by complex biological processes that involve a diverse number of cell types; complex interactions between cells and tissues; the activation of the immune system and the activation of the angiogenic process.
A typical healing process can be divided into 5 distinct, but closely related, stages: clotting stage, acute inflammation stage, matrix deposition stage, capillary formation stage and re-epithelialisation stage. A diverse number of factors control each of these stages. Deficiencies in any aspect of the process can result in defective wound healing. Thus, a ‘normal’ healing process can be defective as a result of either intrinsic or external factors, which manifest as ‘abnormal non-healing’ or ‘chronic’ wounds. It is these ‘non-healing’ or chronic wounds that present the greatest challenge to the quality of a patient's life and mounting expenses to the healthcare system.
Although some common clinical/pathological factors may assist in pre judging if a wound is ‘healing’ or ‘non-healing’, or if an acute wound becomes chronic, there is no specific laboratory test(s) to distinguish wound type. Additionally, there is no clear way to define how to predict the healing process and a patient's likely response to treatment in wound care.